Hyo-Gyoung Kang

Polymorphisms in Telomere Maintenance Genes and Risk of Lung Cancer

This study was conducted to comprehensively evaluate the associations between polymorphisms in telomere maintenance genes (TERT, TRF1, TNKS1, TRF2, RAP1, and POT1) and lung cancer risk. We captured 35 polymorphisms in the genes and determined their frequencies in 27 healthy Koreans. Ten haplotype-tagging polymorphisms were examined in a case-control study that consisted of 720 lung cancer patients and 720 healthy controls. The TERT rs2735940 g.C > T and rs2736098 g.G > A, and TNKS1 rs6985140 g.A > G were significantly associated with the risk of lung cancer. In the haplotype analysis, the TERT rs2735940T/rs2736098A haplotype (ht4) was associated with a significantly increased risk of lung cancer compared with the rs2735940C/rs2736098G haplotype (adjusted odds ratio, 1.26; 95% confidence interval, 1.07-1.50; P = 0.008). When the TERT ht4 and TNKS1 rs6985140G as risk alleles, the risk of lung cancer increased in a dose-dependent manner as the number of risk alleles increased (Ptrend < 0.001). Subjects with two to four risk alleles were at a significantly increased risk of lung cancer (adjusted odds ratio, 1.67; 95% confidence interval, 1.23-2.27; P = 0.001) compared with subjects with zero risk allele. These findings suggest that genetic variants in the TERT and TNKS1 genes contribute to genetic susceptibility to lung cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(10):2773–81)

Replication of results of genome-wide association studies on lung cancer susceptibility loci in a Korean population.

Background and objective:  Genome‐wide association studies (GWAS) have identified the three chromosomal regions, 5p15, 6p21 and 15q25, as being associated with lung cancer risk in European populations. This study was performed to confirm these associations in Korean patients with lung cancer.

Association of a common AGO1 variant with lung cancer risk: a two-stage case-control study.

Based on the important role of microRNA (miRNA) biosynthesis genes in carcinogenesis, we hypothesized that polymorphisms in the miRNA biosynthesis genes may modulate susceptibility to lung cancer. To test this hypothesis, we conducted a two‐stage study to evaluate the associations between single nucleotide polymorphisms (SNPs) in the miRNA biosynthesis genes and the risk of lung cancer. In stage 1 of the study, 24 SNPs in the 11 miRNA biosynthesis genes (DROSHA, DGCR8, RAN, XPO5, DICER, AGO1, AGO2, HIWI, GEMIN3, GEMIN4, and TRBP) were genotyped in 100 lung cancer patients and 100 healthy controls using a sequenome mass spectrometry‐based genotyping assay. One promising SNP (AGO1 rs636832A > G) was selected for stage 2 of the study, and genotyped by a melting‐curve analysis using fluorescence‐labeled hybridization probes in an independent set of 552 cases and 552 controls. The AGO1 rs636832A > G exhibited highly consistent results between the two stages of the study. In combined analysis, the 636832A > G was associated with a significantly decreased risk of lung cancer in a dose‐dependent manner (Ptrend = 6.0 × 10−4). Individuals with at least one rs636832G allele were at a significantly decreased risk of lung cancer compared with those with the AA genotype (adjusted odds ratio = 0.67, 95% confidence interval = 0.53–0.84, P = 4.0 × 10−4). This finding suggests that the AGO1 rs636832A > G might be a useful marker for determining the susceptibility to lung cancer and that the AGO1 gene might be involved in the development of lung cancer.

Polymorphisms in the hMSH2 Gene and the Risk of Primary Lung Cancer

Polymorphisms in the DNA repair genes may be associated with differences in the capacity to repair DNA damage, and so this can influence an individuals susceptibility to lung cancer. To test this hypothesis, we investigated the association of hMSH2 −118T>C, IVS1+9G>C, IVS10+12A>G, and IVS12−6T>C genotypes and their haplotypes with the risk of lung cancer in a Korean population. The hMSH2 genotypes were determined in 432 lung cancer patients and in 432 healthy controls who were frequency matched for age and gender. The hMSH2 haplotypes were estimated based on a Bayesian algorithm using the Phase program. The presence of at least one IVS10+12G allele was associated with a significantly decreased risk of adenocarcinoma, as compared with the IVS10+12AA genotype [adjusted odds ratio (OR), 0.59; 95% confidence interval (95% CI), 0.40-0.88; P = 0.01], and the presence of at least one IVS12-6C allele was associated with a significantly increased risk of adenocarcinoma, as compared with the IVS12-6TT genotype (adjusted OR, 1.52; 95% CI, 1.02-2.27; P = 0.04). Consistent with the results of the genotyping analysis, the TGGT haplotype with no risk allele was associated with a significantly decreased risk of adenocarcinoma, as compared with the TCAC haplotype with two risk allele [i.e., IVS10+12A and IVS12-6C allele; adjusted OR, 0.49; 95% CI, 0.30-0.78; P = 0.003 and Pc (Bonferroni corrected P value) = 0.012]. The effect of the hMSH2 haplotypes on the risk of adenocarcinoma was statistically significant in the never smokers and younger individuals (adjusted OR, 0.45; 95% CI, 0.27-0.75; P = 0.002 and Pc = 0.004; and adjusted OR, 0.44; 95% CI, 0.23-0.85; P = 0.014 and Pc = 0.028, respectively) but not in the ever-smokers and older individuals. These results suggest that the hMSH2 polymorphisms and their haplotypes may be an important genetic determinant of adenocarcinoma of the lung, particularly in never smokers. (Cancer Epidemiol Biomarkers Prev 2006;15(4):762–8)

Polymorphisms in the Caspase7 gene and the risk of lung cancer

BACKGROUND Caspase7 (CASP7) is an executioner CASP that conducted a coordinated program of proteolysis that results in the destruction of critical cell structures, and it plays an important role in the development and progression of cancer. The purpose of this study is to comprehensively evaluate potential functional polymorphisms in the CASP7 gene in relation to the risk of lung cancer. METHODS We first captured seven single nucleotide polymorphisms (SNPs) in the regulating region, exons and exon-intron boundaries of the CASP7 gene using public database and then determined their frequencies in 27 healthy Korean individuals. Next, we examined four SNPs (rs12415607g.C>A; rs11593766g.T>G; rs2227310g.C>G; and rs10787498g.T>C) in a case-control study that consisted of 720 lung cancer patients and 720 healthy controls. RESULTS Of the four SNPs studied in the case-control study, only the distribution of the rs2227310g.C>G genotypes differed significantly between the cases and controls (P=0.03). The rs2227310 GG genotype was associated with a significantly increased risk of lung cancer when compared with the rs2227310 CC genotype [adjusted odds ratio (OR)=1.42, 95% confidence interval (CI)=1.05-1.93, P=0.02] and with the combined rs2227310 CC and CG genotype (adjusted OR=1.38, 95% CI=1.05-1.81, P=0.02). Consistent with the results of genotyping analysis, the ATGT haplotype (rs12415607A/rs11593766T/rs2227310G/rs10787498T) was associated with a significantly increased risk of lung cancer when compared to other haplotypes (adjusted OR=1.21, 95% CI=1.04-1.42, P=0.02). CONCLUSION These results suggest that the CASP7 polymorphisms contribute to the genetic susceptibility to lung cancer.

AKT1 polymorphisms and survival of early stage non-small cell lung cancer†

This study was conducted to investigate the impact of polymorphisms in the AKT1 gene on the survival of early stage non‐small cell lung cancer (NSCLC) patients.

Polymorphisms in the caspase genes and the risk of lung cancer.

Introduction: Caspases (CASPs) are important regulators and executioners in apoptosis pathway and play a crucial role in the development and progression of cancer. On the basis of the interactions of CASPs in the apoptotic pathway, we evaluated the association between 11 polymorphisms of CASP3, 6, 7, 8, 9, and 10 genes and the risk of lung cancer. Methods: The genotypes were determined in 720 patients with lung cancer and 720 healthy controls frequency matched for age and gender. Results: In individual polymorphism analysis, the CASP7 rs2227310C>G and CASP9 rs4645981C>T were associated with 1.40-fold and 1.28-fold increased risk of lung cancer under recessive and dominant models for the variant allele of each polymorphism, respectively. In the case of the CASP3 77G>A, subjects with the GG genotype were at a 1.19-fold increased risk of lung cancer compared with those with at least one variant allele. When the three polymorphisms were combined, the risk of lung cancer increased in a dose-dependent manner as the number of risk genotypes increased (ptrend <0.001). Subjects with two and three risk genotypes carried a significantly increased risk of lung cancer compared with those with zero risk genotype (adjusted odds ratio = 1.56, 95% confidence interval = 1.14–2.13, p = 0.005 and adjusted odds ratio = 2.54, 95% confidence interval = 1.28–5.02, p = 0.008, respectively). Conclusions: These results suggest that a combined analysis of these three CASP gene polymorphisms might better predict the risk of lung cancer than analysis of a single polymorphism.

Polymorphisms in DNA repair and apoptosis-related genes and clinical outcomes of patients with non-small cell lung cancer treated with first-line paclitaxel-cisplatin chemotherapy

This study was conducted to analyze a comprehensive panel of single nucleotide polymorphisms (SNPs) in genes in DNA repair and apoptosis pathways and determine the relationship between polymorphisms and treatment outcomes of patients with non-small cell lung cancer (NSCLC) treated with first-line paclitaxel-cisplatin chemotherapy. Three hundred eighty two patients with NSCLC were enrolled. Seventy-four SNPs in 48 genes (42 SNPs in 27 DNA repair pathway genes and 32 SNPs in 21 apoptotic pathway genes) were genotyped and their associations with chemotherapy response and overall survival (OS) were analyzed. Among SNPs in DNA repair genes, BRCA1 rs799917 was significantly associated with both chemotherapy response and OS. XRCC1 rs25487 exhibited a significant association with chemotherapy response and ERCC2 rs1052555 with OS. Four SNPs in apoptotic genes (TNFRSF1B rs1061624, BCL2 rs2279115, BIRC5 rs9904341, and CASP8 rs3769818) were significantly associated with OS, but not with response to chemotherapy. When the six SNPs which were associated with OS in individual analysis were combined, OS decreased as the number of bad genotypes increased (P(trend) = 2 × 10(-6)). Patients with 3, and 4-6 bad genotypes had significantly worse OS compared with those carrying 0-2 bad genotypes (adjusted hazard ratio [aHR] = 1.54, 95% CI = 1.14-2.08, P = 0.005; aHR = 2.10, 95% CI = 1.55-2.85, P = 2 × 10(-6), respectively). In conclusion, these findings suggest that the six SNPs identified, particularly their combined genotypes, could be used as biomarkers predicting chemotherapy response and survival of NSCLC patients treated with first-line paclitaxel-cisplatin chemotherapy.

Dual roles of a variable number of tandem repeat polymorphism in the TERT gene in lung cancer

This study was conducted to determine the impact of a functional tandem repeat minisatellite (MNS16A) polymorphism in the telomerase reverse transcriptase (TERT) gene on the risk of lung cancer, as well as on survival of patients with non‐small‐cell lung cancer (NSCLC). The effect of the MNS16A variable number of tandem repeat (VNTR) polymorphism on the risk of lung cancer was evaluated in a case–control study that consisted of 937 lung cancer patients and 943 healthy controls. The effect of the polymorphism on survival outcome was evaluated in 703 patients with surgically resected NSCLC. Compared with the VNTR‐302 allele, the VNTR‐243 allele was associated with a significantly increased risk of lung cancer (adjusted odds ratio, 1.55; 95% confidence interval [CI], 1.07–2.25; P = 0.02). In addition, the genotypes carrying at least one VNTR‐243 allele were associated with a significantly increased risk of lung cancer compared with the genotypes with no VNTR‐243 allele (adjusted odds ratio, 1.61; 95% CI, 1.09–2.38; P = 0.02). In contrast to the effect of the polymorphism on the risk of lung cancer, the genotypes carrying at least one VNTR‐243 allele were associated with a significantly better overall survival in patients with surgically resected NSCLC (adjusted hazard ratio, 0.51; 95% CI, 0.28–0.93; P = 0.03). These findings suggest that the MNS16A VNTR polymorphism in the TERT gene has dual, conflicting roles in lung carcinogenesis. This polymorphism may increase the risk of lung cancer development, and may improve survival in lung cancer patients. (Cancer Sci 2011; 102: 144–149)

Comprehensive analysis of DNA repair gene polymorphisms and survival in patients with early stage non-small-cell lung cancer.

This study was conducted to analyze a comprehensive panel of single nucleotide polymorphisms (SNP) in DNA repair genes to determine the relationship between polymorphisms and the survival outcome of patients with early stage non‐small‐cell lung cancer (NSCLC). Three hundred and ten consecutive patients with surgically resected NSCLC were enrolled. Forty‐eight SNP in 27 DNA repair genes were genotyped and their associations with overall survival (OS) and disease‐free survival (DFS) were analyzed. Individually, six SNP exhibited significant associations with survival outcome. When the six SNP were combined, OS and DFS decreased as the number of bad genotypes increased (Ptrend < 0.0001 for both). Patients with three, and four or five bad genotypes had a significantly worse OS and DFS compared with those carrying zero or one bad genotypes (adjusted hazard ratio [aHR] for OS = 3.53, 95% confidence interval [CI] = 1.25–9.97, P = 0.02, and aHR for DFS = 3.31, 95% CI = 1.41–7.76, P = 0.006; and aHR for OS = 5.47, 95% CI = 1.87–16.00, P = 0.002, and aHR for DFS = 4.42, 95% CI = 1.82–10.74, P = 0.001, respectively). These findings suggest that the six SNP identified can be used as prognostic markers for patients with surgically resected early stage NSCLC. (Cancer Sci 2010; 101: 2436–2442)